This invention relates to an apparatus for transporting invalids within a confined area. There are available numerous devices for effecting movement of patients who are otherwise classified as invalids. Most of the prior art devices permit the patient to be raised or lowered and also permit the patient to be swiveled about a vertical support member. As disclosed in U.S. Pat. 2,725,093 to Saelene the apparatus, while being able to move a patient vertically as well as circumferentially, it is necessary that an operator always be present when the apparatus is in use. Other efforts to provide a patient lifting apparatus are very complex as is illustrated by U.S. Pat. No. 3,694,829 to Bakker. The area of travel into which the lift apparatus may place the patient is limited. In many prior art devices it is not possible to permit the patient to be lowered below floor level as in the case of placing a patient in a whirlpool or bathtub that is below floor level. Exemplary of such a device would be U.S. Pat. No. 3,877,421 to Brown.
With today's high cost of labor, it becomes increasingly important that certain patients who are not totally incapacitated be able to operate the lift devices on their own volition. This eliminates the need for an attendant to be constantly present when the apparatus is being used. As can be seen from a review of the above-referenced patents, the particular mechanical structure used to cause the lift platforms or chairs to be moved is somewhat limited in its realm of travel; many permit the lift to be merely raised or lowered and do not provide for circular motion. Reference may be had to U.S. Pat. No. 3,940,808 to Bartholomew for such a device which also does not permit the patient to be lowered below floor level.
A similar device is shown in U.S. Pat. No. 4,075,719 to Sullivan which, once again, requires an operator for assistance during use of the apparatus and does not permit articulated movement or placement of the patient carrying platform nor does it permit the patient to be lowered below floor level. More recent patents are devoted to mechanisms for moving wheelchair patients into and out of motorized vehicles such as U.S. Pat. No. 4,133,437 to Gates.
Many of the prior art devices use pinion and gear drives to effect movement of the patient lift apparatus. Others use pneumatic controls.